Spatially and temporally systematic hydrologic changes within large geoengineered landslides, Cromwell Gorge, New Zealand, induced by multiple regional earthquakes

10.26686/wgtn.13819244 ◽

2021 ◽

Author(s):

GA O'Brien ◽

SC Cox ◽

John Townend

Keyword(s):

Groundwater Level ◽

Spectral Characteristics ◽

Seismic Energy ◽

High Amplitude ◽

Ground Acceleration ◽

Earthquake Parameters ◽

Groundwater Levels ◽

Time To Peak ◽

Long Duration ◽

Groundwater Level Changes

©2016. American Geophysical Union. All Rights Reserved. Geoengineered groundwater systems within seven large (23 × 104–9 × 106 m2), deep-seated (40–300 m), previously slow-creep (2–5 mm/yr.) schist landslides in the Cromwell Gorge responded systematically to 11 large (Mw > 6.2) earthquakes at epicentral distances of 130–630 km between 1990 and 2013. Landslide groundwater is strongly compartmentalized and often overpressured, with permeability of 10−17 to 10−13 m2 and flow occurring primarily through fracture and crush zones, hindered by shears containing clayey gouge. Hydrological monitoring recorded earthquake-induced meter- or centimeter-scale changes in groundwater levels (at 22 piezometers) and elevated drainage discharge (at 11 V notch weirs). Groundwater level changes exhibited consistent characteristics at all monitoring sites, with time to peak-pressure changes taking ~1 month and recovery lasting 0.7–1.2 years. Changes in weir flow rate near instantaneous (peaking 0–6 h after earthquakes) and followed by recession lasting ~1 month. Responses at each site were systematic from one earthquake to another in terms of duration, polarity, and amplitude. Consistent patterns in amplitude and duration have been compared between sites and with earthquake parameters (peak ground acceleration (PGA), seismic energy density (e), shaking duration, frequency bandwidth, and site amplitude). Shaking at PGA ~0.27% g and e ~ 0.21 J m−3 induced discernable gorge-wide hydrological responses at thresholds comparable to other international examples. Groundwater level changes modeled using a damped harmonic oscillator characterize the ability of the system to resist and recover from extrinsic perturbations. The observed character of response reflects spectral characteristics as well as energy. Landslide hydrological systems appear most susceptible to damage and hydraulic changes when earthquakes emit broad-frequency, long-duration, high-amplitude ground motion.

Seismological and Hydrogeological Controls on New Zealand-Wide Groundwater Level Changes Induced by the 2016 Mw 7.8 Kaikōura Earthquake

10.26686/wgtn.13792751.v1 ◽

2021 ◽

Author(s):

KC Weaver ◽

SC Cox ◽

John Townend ◽

H Rutter ◽

IJ Hamling ◽

...

Keyword(s):

New Zealand ◽

Water Level ◽

Groundwater Level ◽

Ground Acceleration ◽

Permeability Enhancement ◽

Water Level Changes ◽

Stress Changes ◽

Kaikoura Earthquake ◽

Directivity Effects ◽

Groundwater Level Changes

© 2019 K. C. Weaver et al. The 2016 Mw 7.8 Kaikōura earthquake induced groundwater level changes throughout New Zealand. Water level changes were recorded at 433 sites in compositionally diverse, young, shallow aquifers, at distances of between 4 and 850 km from the earthquake epicentre. Water level changes are inconsistent with static stress changes but do correlate with peak ground acceleration (PGA). At PGAs exceeding 2 m/s2, water level changes were predominantly persistent increases. At lower PGAs, there were approximately equal numbers of persistent water level increases and decreases. Shear-induced consolidation is interpreted to be the predominant mechanism causing groundwater changes at accelerations exceeding 2 m/s2, whereas permeability enhancement is interpreted to predominate at lower levels of ground acceleration. Water level changes occur more frequently north of the epicentre, as a result of the fault's northward rupture and resulting directivity effects. Local hydrogeological conditions also contributed to the observed responses, with larger water level changes occurring in deeper wells and in well-consolidated rocks at equivalent PGA levels.

Earthquake-induced hydrologic changes in the geoengineered schist landslides of Cromwell Gorge, Central Otago

10.26686/wgtn.17007601.v1 ◽

2021 ◽

Author(s):

◽

Grant O'Brien

Keyword(s):

Groundwater Level ◽

Recovery Time ◽

Hydraulic Properties ◽

Peak Pressure ◽

Pressure Change ◽

Monitoring Site ◽

Flow Rates ◽

Time To Peak ◽

Hydrological Responses ◽

Groundwater Level Changes

<p>Geoengineered groundwater systems located within seven large (> 100 ha surface area), deep-seated, slow-creep schist landslides in Cromwell Gorge (Otago, New Zealand) are observed to respond systematically to 10 large (>Mw6.2), regional earthquakes at epicentral distances of 130-630 km. The permeabilities of the schist landslides have previously been reported to be c. 1 x 10⁻¹⁷ - 4 x 10⁻⁶ m2 and the permeability structure is dominated by large fracture zones. Of the 315 hydrological instruments in the gorge for which data have been analysed, 21 monitoring well piezometers record repeated metre- or centimetre-scale groundwater level changes, and 12 underground V-notch weirs record elevated flow rates induced by the same earthquakes. Groundwater level changes exhibit consistent temporal characteristics at all monitoring sites, namely a time to peak pressure change on the order of one month and a subsequent recovery period on the order of one year. Changes in weir flow rate are near-instantaneous with maximum flow rates reached within 0-6 hours, followed by recession periods on the order of one month. Hydrological responses to different earthquakes at each monitoring site are systematic in terms of polarity and amplitude. This comprehensive dataset enables consistent patterns in the amplitude, time to peak pressure change and recovery time of groundwater level changes, and elevated weir discharge volumes in response to earthquake shaking to be documented. Earthquakes inducing hydrological responses have been categorised into five categories based on shaking characteristics (duration, bandwidth and amplitude). Larger hydrological responses and proportionally shorter time to peak pressure change and recovery time are associated with long duration (25-50 s or longer), high-amplitude, broad bandwidth shaking. The larger amplitudes of hydrological response and proportionally shorter times to peak pressure change and recovery times, are interpreted to represent greater temporary enhancement of the landslides hydraulic properties, particularly permeability. Understanding how earthquakes can enhance or otherwise affect hydraulic properties such as permeability in fractured reservoirs is intrinsically important and may prove of economic utility for both the geothermal and hydrocarbon energy sectors.</p>

Earthquake-induced hydrologic changes in the geoengineered schist landslides of Cromwell Gorge, Central Otago

10.26686/wgtn.17007601 ◽

2021 ◽

Author(s):

◽

Grant O'Brien

Keyword(s):

Groundwater Level ◽

Recovery Time ◽

Hydraulic Properties ◽

Peak Pressure ◽

Pressure Change ◽

Monitoring Site ◽

Flow Rates ◽

Time To Peak ◽

Hydrological Responses ◽

Groundwater Level Changes

<p>Geoengineered groundwater systems located within seven large (> 100 ha surface area), deep-seated, slow-creep schist landslides in Cromwell Gorge (Otago, New Zealand) are observed to respond systematically to 10 large (>Mw6.2), regional earthquakes at epicentral distances of 130-630 km. The permeabilities of the schist landslides have previously been reported to be c. 1 x 10⁻¹⁷ - 4 x 10⁻⁶ m2 and the permeability structure is dominated by large fracture zones. Of the 315 hydrological instruments in the gorge for which data have been analysed, 21 monitoring well piezometers record repeated metre- or centimetre-scale groundwater level changes, and 12 underground V-notch weirs record elevated flow rates induced by the same earthquakes. Groundwater level changes exhibit consistent temporal characteristics at all monitoring sites, namely a time to peak pressure change on the order of one month and a subsequent recovery period on the order of one year. Changes in weir flow rate are near-instantaneous with maximum flow rates reached within 0-6 hours, followed by recession periods on the order of one month. Hydrological responses to different earthquakes at each monitoring site are systematic in terms of polarity and amplitude. This comprehensive dataset enables consistent patterns in the amplitude, time to peak pressure change and recovery time of groundwater level changes, and elevated weir discharge volumes in response to earthquake shaking to be documented. Earthquakes inducing hydrological responses have been categorised into five categories based on shaking characteristics (duration, bandwidth and amplitude). Larger hydrological responses and proportionally shorter time to peak pressure change and recovery time are associated with long duration (25-50 s or longer), high-amplitude, broad bandwidth shaking. The larger amplitudes of hydrological response and proportionally shorter times to peak pressure change and recovery times, are interpreted to represent greater temporary enhancement of the landslides hydraulic properties, particularly permeability. Understanding how earthquakes can enhance or otherwise affect hydraulic properties such as permeability in fractured reservoirs is intrinsically important and may prove of economic utility for both the geothermal and hydrocarbon energy sectors.</p>

Groundwater Level Changes in Shallow Aquifer of Yogyakarta City, Indonesia: Distribution and Causes

Journal of Applied Geology ◽

10.22146/jag.27584 ◽

2017 ◽

Vol 1 (2) ◽

pp. 89 ◽

Cited By ~ 1

Author(s):

Liliane Manny ◽

Rilo Restu Surya Atmaja ◽

Doni Prakasa Eka Putra

Keyword(s):

Population Density ◽

Groundwater Level ◽

Spatial Information ◽

Shallow Aquifer ◽

Sewer System ◽

Groundwater Levels ◽

Urban Recharge ◽

The City ◽

Groundwater Level Changes ◽

Yogyakarta City

The population in Yogyakarta City, Indonesia has increased since 1970, resulting in high groundwater utilization. This normally results in a decline of groundwater level in shallow aquifer beneath the city. However, expansion of the city and urbanization effects can also have the opposite effect and lead to a rise of groundwater levels due to urban recharge. This study investigates groundwater level changes in Yogyakarta City during a time period of 30 years between 1985 and 2015. Collected data in this research are groundwater level, rainfall, population density, sewer system, and land use. Overlaying various spatial information reveals a pattern of groundwater level rise in some areas of the city by 0–12 m, whilst in other areas a decline of 0–9 m is discovered. Rising groundwater levels are mainly found in areas moderate to high population density where sewer system networks have been installed. The rising of groundwater levels is this expected to be caused by urban recharge and sewers leakage.

Foundation design on problematic soils with high underground water level

10.7764/rdlc.19.3.233-245 ◽

2020 ◽

Vol 19 (3) ◽

pp. 233-245

Author(s):

Nazile Ural ◽

◽

Abdulselam Gergin

Keyword(s):

Groundwater Level ◽

Underground Water ◽

Soil Profiles ◽

Foundation Design ◽

Load Bearing Capacity ◽

Groundwater Levels ◽

Design And Implementation ◽

Problematic Soils ◽

Underground Water Level ◽

Groundwater Level Changes

In this study, the foundation systems of a structure on different soil profiles and different groundwater levels are modeled and analyzed. Several difficulties encounter during the basic design and implementation phases. In particular, the high groundwater level, the load on the soil under the load-bearing capacity, liquefaction causes many problems such as emergence. Within the scope of this study, foundation systems which based on six different soil profiles with a high groundwater level modeled with Plaxis 2D program. Thus, the stress and displacement conditions of the soil about the foundation system as a result of the soil properties and groundwater level changes in problematic soils investigated.

Seismological and Hydrogeological Controls on New Zealand-Wide Groundwater Level Changes Induced by the 2016 Mw7.8 Kaikōura Earthquake

Geofluids ◽

10.1155/2019/9809458 ◽

2019 ◽

Vol 2019 ◽

pp. 1-18 ◽

Cited By ~ 3

Author(s):

K. C. Weaver ◽

S. C. Cox ◽

J. Townend ◽

H. Rutter ◽

I. J. Hamling ◽

...

Keyword(s):

New Zealand ◽

Water Level ◽

Groundwater Level ◽

Ground Acceleration ◽

Permeability Enhancement ◽

Water Level Changes ◽

Stress Changes ◽

Kaikoura Earthquake ◽

Directivity Effects ◽

Groundwater Level Changes

The 2016 Mw7.8 Kaikōura earthquake induced groundwater level changes throughout New Zealand. Water level changes were recorded at 433 sites in compositionally diverse, young, shallow aquifers, at distances of between 4 and 850 km from the earthquake epicentre. Water level changes are inconsistent with static stress changes but do correlate with peak ground acceleration (PGA). At PGAs exceeding ~2 m/s2, water level changes were predominantly persistent increases. At lower PGAs, there were approximately equal numbers of persistent water level increases and decreases. Shear-induced consolidation is interpreted to be the predominant mechanism causing groundwater changes at accelerations exceeding ~2 m/s2, whereas permeability enhancement is interpreted to predominate at lower levels of ground acceleration. Water level changes occur more frequently north of the epicentre, as a result of the fault’s northward rupture and resulting directivity effects. Local hydrogeological conditions also contributed to the observed responses, with larger water level changes occurring in deeper wells and in well-consolidated rocks at equivalent PGA levels.

Seismological and Hydrogeological Controls on New Zealand-Wide Groundwater Level Changes Induced by the 2016 Mw 7.8 Kaikōura Earthquake

10.26686/wgtn.13792751 ◽

2021 ◽

Author(s):

KC Weaver ◽

SC Cox ◽

John Townend ◽

H Rutter ◽

IJ Hamling ◽

...

Keyword(s):

New Zealand ◽

Water Level ◽

Groundwater Level ◽

Ground Acceleration ◽

Permeability Enhancement ◽

Water Level Changes ◽

Stress Changes ◽

Kaikoura Earthquake ◽

Directivity Effects ◽

Groundwater Level Changes

© 2019 K. C. Weaver et al. The 2016 Mw 7.8 Kaikōura earthquake induced groundwater level changes throughout New Zealand. Water level changes were recorded at 433 sites in compositionally diverse, young, shallow aquifers, at distances of between 4 and 850 km from the earthquake epicentre. Water level changes are inconsistent with static stress changes but do correlate with peak ground acceleration (PGA). At PGAs exceeding 2 m/s2, water level changes were predominantly persistent increases. At lower PGAs, there were approximately equal numbers of persistent water level increases and decreases. Shear-induced consolidation is interpreted to be the predominant mechanism causing groundwater changes at accelerations exceeding 2 m/s2, whereas permeability enhancement is interpreted to predominate at lower levels of ground acceleration. Water level changes occur more frequently north of the epicentre, as a result of the fault's northward rupture and resulting directivity effects. Local hydrogeological conditions also contributed to the observed responses, with larger water level changes occurring in deeper wells and in well-consolidated rocks at equivalent PGA levels.

Characterization of spatial coseismic response of groundwater levels in shallow and deep parts of an alluvial plain to different earthquakes

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-9-5317-2012 ◽

2012 ◽

Vol 9 (4) ◽

pp. 5317-5354

Author(s):

M. Parvin ◽

N. Tadakuma ◽

H. Asaue ◽

K. Koike

Keyword(s):

Groundwater Level ◽

Groundwater Resources ◽

Shallow Groundwater ◽

Seismic Energy ◽

Large Earthquake ◽

Deep Groundwater ◽

Groundwater Levels ◽

Pressure Changes ◽

Relationship Of

Abstract. Coseismic changes in groundwater levels have been investigated in many places throughout the world, but most studies have focused on the effects of one large earthquake. Few studies have looked at the spatial patterns of level changes in response to several earthquakes, or at the relationship of the patterns to shallow and deep groundwater in the same area. The aim of this study was to investigate these patterns and to construct a model of hydraulic responses. We selected the Kumamoto City area in southwest Japan, a region with one of the richest groundwater resources in Japan, as our study site. Data from hourly measurements of groundwater levels in 54 wells were used to characterize the coseismic spatial responses to four large earthquakes that occurred in 2000, 2001, 2005, and 2008. Although the distance to the epicenter (12 to 2573 km), and seismic energy (Mw = 4.8 to 8.0) of these earthquakes varied, systematic groundwater level changes were observed in the range of 0.01 to 0.67 m. The zones where coseismic rises were observed were generally wider for deep groundwater than for shallow groundwater. We observed general trends in the changes in groundwater levels, and calculated pressure changes, in the deep groundwater, but the coseismic increases or decreases in compressive stress in the shallow groundwater were variable, depending on the distance to the earthquake epicenter. We developed a conceptual model of the mechanism underlying this phenomenon and also investigated the importance of Togawa lava, consisting of porous andesite and forming a main aquifer, in determining the pattern of groundwater level change.

Investigating Groundwater Condition and Seawater Intrusion Status in Coastal Aquifer Systems of Eastern India

Water ◽

10.3390/w13141952 ◽

2021 ◽

Vol 13 (14) ◽

pp. 1952

Author(s):

Subrata Halder ◽

Lingaraj Dhal ◽

Madan K. Jha

Keyword(s):

Groundwater Quality ◽

Seawater Intrusion ◽

Groundwater Level ◽

Coastal Aquifer ◽

Quality Data ◽

Confined Aquifer ◽

Groundwater Levels ◽

Post Monsoon ◽

Aquifer Systems ◽

Sustainable Water Supply

Providing sustainable water supply for domestic needs and irrigated agriculture is one of the most significant challenges for the current century. This challenge is more daunting in coastal regions. Groundwater plays a pivotal role in addressing this challenge and hence, it is under growing stress in several parts of the world. To address this challenge, a proper understanding of groundwater characteristics in an area is essential. In this study, spatio-temporal analyses of pre-monsoon and post-monsoon groundwater-levels of two coastal aquifer systems (upper leaky confined and underlying confined) were carried out in Purba Medinipur District, West Bengal, India. Trend analysis of seasonal groundwater-levels of the two aquifers systems was also performed using Mann-Kendall test, Linear Regression test, and Innovative Trend test. Finally, the status of seawater intrusion in the two aquifers was evaluated using available groundwater-quality data of Chloride (Cl−) and Total Dissolve Solids (TDS). Considerable spatial and temporal variability was found in the seasonal groundwater-levels of the two aquifers. Further, decreasing trends were spotted in the pre-monsoon and post-monsoon groundwater-level time series of the leaky confined and confined aquifers, except pre-monsoon groundwater-levels in Contai-I and Deshpran blocks, and the post-monsoon groundwater-level in Ramnagar-I block for the leaky confined aquifer. The leaky confined aquifer in Contai-I, Contai-III, and Deshpran blocks and the confined aquifer in Nandigram-I and Nandigram-II blocks are vulnerable to seawater intrusion. There is an urgent need for the real-time monitoring of groundwater-levels and groundwater quality in both the aquifer systems, which can ensure efficient management of coastal groundwater reserves.